Information

Memory Products
9
Serial SRAM
Microchip’s Serial SRAM family provides a way to easily and
inexpensively add external RAM to almost any application.
These serial devices use less power and fewer I/O connec-
tions than traditional parallel SRAM, and they allow you to
use a smaller microcontroller with additional on-board RAM.
Microchip’s SPI-compatible Serial SRAM devices are available
in 64 Kbits, 256 Kbits, 512 Kbits and 1 Mbit options and up to
20 MHz. The 512 Kbits and 1 Mbit parts support data backup
via an external battery/coin cell connected Vbat pin. These
8-pin devices have unlimited endurance and zero write times.
1.5–1.95V 2.7–3.6V
1 Mbit
23A1024/20 MHz 23LC1024/20 MHz
512 Kbits
23A512/20 MHz 23LC512/20 MHz
256 Kbits
23A256/16 MHz 23K256/20 MHz
64 Kbits
23A640/16 MHz 23K640/20 MHz
Key Features
• SPI Bus, 20 MHz
• Volatile memory
• Operating voltage: 1.5–1.95V and 2.7–3.6V
• Innite endurance
• Zero write speeds
• Low-power consumption
• Automotive Grade 1 with PPAP support
Key Benets
• Lower system costs – innovative products, tiny packages,
low-power consumption, fewer I/O pins, small form factor
• Save I/O pins on the MCU – more compact designs, add
additional features
• Secure data with write-protect options
• Robust designs with broad operating conditions
Typical Applications
• Metering
• Point-of-Sale (POS) terminals
• Printers
• Internet radio
• Ethernet
• Wi-Fi
• Replace parallel RAM
• Any application needing low-cost RAM
Flexible RAM Expansion
Add features to your current microcontroller and get to market
faster.
• Add functionality to your current design
• No need to buy a larger microcontroller just for the RAM
• Familiar 4-pin SPI interface
• Reduce cost in your current design
• Scratchpad, buering, high-endurance applications
The Serial SRAM Advantage
Feature Traditional Parallel SRAM Microchip’s Serial SRAM
I/O Connection to MCU
16–20 4
Standby Current
3 mA 1 μA
Active Current
50 mA 1–10 mA
Lowest Operating Voltage
3.0V 1.7V
Footprint
100 mm
2
20 mm
2
Smallest Packages
28-pin TSSOP, 28-pin SOIC 8-pin TSSOP, 8-pin SOIC
MCU
RAM
MCU
Parallel
SRAM
RAM
Parallel
16–20
I/O lines
. . .
MCU
Serial
SRAM
RAM
SPI
4 I/O lines
Stand-alone Serial SRAM offering greater design
flexibility and the opportunity for RAM expansion
MCU
RAM
MCU
Parallel
SRAM
RAM
Parallel
16–20
I/O lines
. . .
MCU
Serial
SRAM
RAM
SPI
4 I/O lines
Stand-alone Serial SRAM offering greater design
flexibility and the opportunity for RAM expansion
MCU
RAM
MCU
Parallel
SRAM
RAM
Parallel
16–20
I/O lines
. . .
MCU
Serial
SRAM
RAM
SPI
4 I/O lines
Stand-alone Serial SRAM offering greater design
flexibility and the opportunity for RAM expansion
Serial SRAM Products
Device
Density
(Organization)
Max. Clock
Frequency
Operating Voltage
(A, K)
Temperature
(I, E) (°C)
Read Current
(mA)
Max. Standby
Current
Packages
Battery
Back-Up
23X640
8 Kbits (64 KB) 20 MHz 1.8V, 3V −40 to +125 3 mA 4 µA PDIP, SOIC, TSSOP No
23X256
32 Kbits (256 KB) 20 MHz 1.8V, 3V −40 to +125 3 mA 4 µA PDIP, SOIC, TSSOP No
23X512
64 Kbits (512 KB) 20 MHz 1.8V, 3V, 5V −40 to +125 3 mA 4 µA PDIP, SOIC, TSSOP Yes
23X1024
125 Kbits (1 MB) 20 MHz 1.8V, 3V, 5V −40 to +125 3 mA 4 µA PDIP, SOIC, TSSOP Yes
1. Voltage Range: A = 1.5–1.95 V, K = 2.7–3.6 V 2. All devices are RoHS-compliant